1. Field of the Invention
The present invention relates to a recording device for recording information on a recording medium consisting essentially of a disk accommodated in a protective case, such as MDs (Mini Disks).
2. Description of the Related Art
Recording media that are protected by a cartridge (protective case), such as magneto-optical disks and optical disks, have recently come into use. FIGS. 22A to 22D show a front-loading system, which is one kind of mechanism for mounting such a disk protected by a cartridge.
Hereinafter, the front-loading system will be described with reference to FIGS. 22A to 22D. As shown in FIGS. 22A to 22D, an object lens 101a of a pickup 101 must go inside a cartridge 113 via a window 113a formed in the cartridge 113. Moreover, a turntable 102 for rotating a disk 112 must go inside the cartridge 113 via a hole (not shown) in the center of the cartridge 113. Accordingly, the cartridge 113 is required to take a loading path such that the cartridge 113 is moved in the direction of arrow A and then moved in the direction of arrow F.
As for methods for recording information on magneto-optical disks, an magnetic field modification overwriting method has come to be used, in which a laser beam emitted from a pickup is focused on a disk so as to increase the temperature thereof, and the magnetic poles of a magnetic head disposed opposite to the pickup with respect to the disk are alternated, whereby information is recorded on the disk. In order to achieve high reliability and low power consumption by the magnetic head according to this recording method, the pickup and the magnetic head are required to maintain highly precise relative locations such that they oppose each other with a disk interposed therebetween.
The mechanism of the pickup 101 and a magnetic head 109 will be described with reference to FIGS. 22A to 22D.
The pickup 101 is attached to guide shafts 103 and 104 which are attached in parallel to a main chassis (not shown), the pickup 101 being slidable along a direction perpendicular to the paper on which FIGS. 22A to 22D are described. A driving grip 105 fixed on the pickup 101 is pressed onto a driving screw 106 attached to the main chassis. Thus, driving force from a sending motor (not shown) is transmitted to the pickup 101 via the driving screw 106, thereby moving the pickup 101 along the direction perpendicular to the paper. A magnetic head attachment angle 107 is fixed on the pickup 101. A magnetic head attachment lever 108 is attached to the magnetic head attachment angle 107 so as to be capable of rotating. The magnetic head 109 is attached to the farthest end in the direction of arrow B of the magnetic head attachment lever 108. The magnetic head attachment lever 108 is loaded by a spring 111 in such a way that the magnetic head 109 is ready to move in the direction of arrow F. An upper face of the magnetic head attachment lever 108 abuts with an axis 110 which can move in the directions of arrows A and B, whereby the position of the magnetic head 109 is maintained.
The cartridge 113 is guided by a cartridge holder (not shown) and is moved in the direction of arrow a from a detachable position shown in FIG. 22A to a snug position shown in FIG. 22B, and then moved in the direction of arrow F from the snug position shown in FIG. 22B to a reproducible position shown in FIG. 22C. The reproducible position (FIG. 22C) is identical with a recordable position shown in FIG. 22D with respect to the position of the cartridge 113.
In the detachable position (FIG. 22A) and in the snug position (FIG. 22B), the magnetic head 109 is in a stand-by state where the magnetic head 109 does not contact the cartridge 113, which travels vertically (i.e., in the direction of arrow E or arrow F) during the loading thereof. In the reproducible position (FIG. 22C), the magnetic head 109 is still detached from the cartridge 113. In the recordable position (FIG. 22D), the magnetic head 109 is in contact with the disk 112 so as to enable recording, the magnetic head 109 having traveled into the cartridge 113 through the window 113b. Vertical movements of the magnetic head 109 are achieved by the rotation of the magnetic head attachment lever 108, which in turn is caused by the axis 110 moving in the directions of arrows A or B so as to abut with the magnetic head attachment lever 108 on different planes. Thus, the magnetic head 109 is retracted vertically with respect to the loading path of the cartridge 113.
However, in the front-loading system, the above-mentioned retraction of the magnetic head 109, which takes the magnetic head 109 out of the loading path exclusively along the vertical direction with respect to the recording face of the disk, may cause a problem in that the magnetic head 109 must be retracted by a large distance along the vertical direction, thereby making it difficult to reduce the thickness of the disk recording/reproduction device. The issue of reduction of the thickness of a disk recording/reproduction device becomes critical when the disk recording/reproduction device is incorporated as an external memory device for a notebook-type personal computer.
In view of the above-mentioned problem, the applicant of the present application has proposed a device in Japanese Patent Application No. 6-150132. In accordance with this device, a magnetic head is so constructed as to be capable of being connected to and detached from a pickup. The magnetic head is detached from the pickup during the loading of a recording medium (disk) so as to be alone moved horizontally, i.e., in parallel to a recording face of the disk, thereby to locate the magnetic head in a retracted position away from a position in which the magnetic head opposes a protective case of the recording medium (hereinafter, this position will be referred to as an "opposing position"). In accordance with this technique, the entire recording/reproduction device can be decreased in thickness as compared with the above-mentioned conventional method where the magnetic head is moved vertically with respect to a recording face of a disk so as to be retracted out of a loading path.
Although the above-mentioned technique proposed in Japanese Laid-Open Patent Application No. 6-150132 achieves reduction in the thickness of the entire device, it requires a complicated mechanism for connecting/disconnecting the magnetic head to/from the pickup, which leads to an increase in the number of movable parts, thereby increasing the possibility of malfunction. Thus, the reliability of the device may not be sufficient. By repetitive connection and disconnection, the relative positions of the magnetic head and the pickup, in particular, may vary although required to be highly precise. This could result in an adverse effect on the recording performance of the device.